TORONTO - Conrad Black's lawyers are asking U.S. authorities to send the Canadian-born businessman to a minimum-security prison -- a privilege usually denied to non-Americans.

Although he's one of Canada's most famous businessmen, Black is currently a citizen of the United Kingdom and facing 6� years in prison in the United States after being convicted of several white-collar crimes by a Chicago jury after a months-long trial last year.

In a letter dated Dec. 27 and filed with the U.S. court system this week, one of Black's lawyers argues that the former newspaper magnate shouldn't be subject to a public safety factor, or PSF, which would prevent him from being sent to a minimum security prison.

"On Mr. Black's behalf, we respectfully request the Bureau of Prisons to waive Mr. Black's alienage-based PSF,'' says the letter signed by lawyers Jeffrey Steinback and Marc Martin.

The lawyers cited his admiration for the United States and his record of business there.

The letter doesn't mention that Black has written recent biographies on two American presidents, Franklin Delano Roosevelt and Richard Nixon, and formerly controlled the Chicago Sun-Times newspaper and numerous other American publications.

However, the letter does mention that he has a home in Palm Beach, Fla. -- media reports have described it as a beachside mansion worth several million dollars -- and is a "resident of Toronto'' where he has another mansion in an elite neighbourhood, although he has been prevented from living there by U.S. restrictions on his travel.

A jury in Chicago convicted Black of fraud and obstruction of justice in July. Black is seeking to appeal those convictions and maintains that he broke no laws.

But because he is not a U.S. citizen, Black is ineligible to serve his time in a minimum-security facility.

His lawyers have previously asked for him to serve his time in the Coleman Federal Correctional Complex in Coleman, Fla., but say in the letter that they'd rather have him go to a minimum security prison in Miami if the waiver is granted.

In making their case, Black's lawyers say that he does not meet the criteria of a public safety factor if he were an American citizen. For instance, he's not a sex offender, threat to government officials and not violent.

"The only real question, then, is whether Mr. Black's status as a deportable alien (he is a citizen of Great Britain) increases the risk that he would abscond if placed in a minimum security facility,'' the lawyers write.

To this, they note that Black has been given considerable latitude by trial judge Amy St. Eve, who has given him until early March to report to prison and who has carefully weighed his risk of flight before and during the trial last year.

"Mr Black has been permitted to travel freely between Chicago and Florida. At sentencing, Judge St. Eve found by clear and convincing evidence that he was neither a flight risk nor a danger in the community.''

If Black is successful in getting a waiver, his lawyers said they will ask for their client to serve time at a minimum-security prison in Miami, in light of his Palm Beach home, so his wife could visit him easily.

Black and two other former executives of Hollinger International Inc. were convicted of three counts of fraud. One other executive was convicted of two fraud charges. Black was also found guilty of one count of obstruction of justice.